1. Field of the Invention
The present invention relates to bicycle frames and more particularly to rear wheel suspension systems for bicycle frames composed of composite materials.
2. Description of the Prior Art
To control any wheeled vehicle, such as a bicycle, the wheels must stay in contact with the surface of the road. This is relatively easy to accomplish on a smooth surface. However, on a rough surface, such as a dirt road or trail, keeping the wheels in contact with the road becomes more difficult and typically requires an elaborate suspension system. Motorcycles have had such elaborate suspension systems for decades, and even a few of these motorcycle suspension systems have been adapted for use on bicycles. These suspension systems, due to the number of moving parts and joints required for them to function, are heavy and complicated. Bicycles are human-powered. A very strong rider can produce only approximately one-half horsepower for short periods of time, and on numerous occasions a rider is forced to push or even carry his bicycle over inhospitable terrain. With the relatively low available horsepower and the need to, on occasion, carry the bicycle, weight becomes an important factor when considering the viability of a bicycle rear wheel suspension system.
Recently, bicycle frames composed of composite materials have been developed. Such bicycle frames are particularly strong yet lightweight. The peculiar mechanical features of composite materials, such as the possible non-circular cross-sectional shapes of frame members and the orientation of the fiber materials which are included within the composite material forming the frame member, are utilized in the instant invention to produce the rear wheel suspension system described and claimed herein.